Frequently Asked Questions

Review the list below for answers to common questions regarding instillation with dwell time using V.A.C. VERAFLO™ Therapy as part of the V.A.C.ULTA™ Therapy System.

Instillation with dwell time (NPWTi-d):

A controlled, automated process in which instilled topical wound solution is slowly introduced into the wound and remains in the wound bed for a defined period of time before being removed by applying negative pressure.

These Frequently Asked Questions are not intended to take the place of the detailed product use and safety information found in the V.A.C.ULTA™ Therapy System Instructions for Use or the V.A.C.® Therapy Clinical Guidelines. KCI recommends that clinicians participate in device in-service and training prior to use of these products.

  • V.A.C. VERAFLO™ Dressing: Small (13.25 in3), Medium (37.65 in3), and Large (56.3 in3)
  • V.A.C. VERAFLO CLEANSE™ Dressing: Medium (≥ 23.51 in3)
  • V.A.C. VERALINK™ Cassette: One size only
  • V.A.C. VERAT.R.A.C. DUO™ Tube Set: One size only

The V.A.C. VERAT.R.A.C. DUO™ Tubing Set and V.A.C. VERALINK™ Cassette.

Dressing: Wounds being treated with the V.A.C.ULTA™ Therapy System should be monitored on a regular basis. In a monitored, non-infected wound, V.A.C.® Dressings and V.A.C. VERAFLO™ Therapy Dressings should be changed every 48 to 72 hours, but no less than 3 times per week, with frequency adjusted by the clinician as appropriate (for details, please refer to the labeling provided in the dressing carton).

Cassette: The V.A.C. VERALINK™ Cassette is for single-patient use. Each V.A.C. VERALINK™ Cassette should not be used for more than 11,250 ml of instillation solution. Refer to institutional guidelines, as applicable.

It is also recommended to change the V.A.C. VERAFLO™ Therapy disposables if the type of the solution instilled is changed. This is to prevent the possibility of two solutions interacting and resulting in undesirable effects to the tissue.

No. The V.A.C.ULTA™ Therapy unit is designed to self-prime the V.A.C. VERALINK™ Cassette under these circumstances:

  • The initial setup
  • Spiking a new solution container following the Solution Bag/Bottle Empty alarm
  • After correctly engaging the cassette following the V.A.C. VERAFLO™ Cassette Not Engaged alarm

Note: Self-priming means the volume displayed on-screen will not increment until the therapy unit has pumped an automatic preset volume to fill the empty tube.

It is recommended that every time the topical solution is changed, both the V.A.C. VERALINK™ Cassette and dressing be are changed.

Because solutions may react with each other; there can be sufficient residual solution in the tubing of the V.A.C. VERALINK™ Cassette or within the dressing to potentially react with the new solution. The reaction could lead to precipitation formation, solution inactivation, or an unforeseen reaction with a system component.

The goal is to supply enough solution to cover as much wound surface as possible without causing the dressing to bulge or swell beyond the shape of the dressing when negative pressure is NOT applied.

Fill Assist—helps the user determine the correct instill volume to use during V.A.C. VERAFLO™ Therapy. This feature allows users to monitor the initial wound fill by manually starting and stopping instillation. Once the appropriate volume is determined and stored in the settings by selecting OK on the Fill Assist screen, the device will instill the same amount of solution automatically during each future instillation with dwell time phase. Reassess the fill volume as the wound proceeds to closure.

Instillation with dwell time (NPWTi-d):

A controlled, automated process in which instilled topical wound solution is slowly introduced into the wound and remains in the wound bed for a defined period of time before being removed by applying negative pressure.

(Please see page 48 of the V.A.C.ULTA™ Therapy System User Manual to learn how to use “Fill Assist”)

The V.A.C.ULTA™ Therapy System is compatible with a variety of topical solutions to meet the needs of a variety of wounds. Please refer to the list of solutions that are compatible with the V.A.C.ULTA™ Therapy System based on KCI in-house testing. KCI does not recommend solutions, provide patient diagnosis, or suggest specific therapies with the topical agents. For guidance on the use of solutions, review the current literature.

The V.A.C. VERAFLO™ Therapy initial drawdown will take approximately 2.5 minutes to establish a seal. This helps minimize the risk of air and solution leaks during therapy by pulling the drape against the skin and allowing it time to cure before instilling solution. SEAL CHECK™ will be active during this phase so the user can observe the dressing for leaks.

The unit will also provide an option to log the disposables used on this screen while waiting for the SEAL CHECK™ to complete.

Material Polyurethane Polyvinyl alcohol Polyurethane Polyurethane
Tear Strength 1 2 3 4
Tensile 1 2 3 4
Hydrophobicity 3 4 2 1

KEY: 1 = Highest relative value; 4 = Lowest relative value

The V.A.C. VERAFLO™ Dressing family is designed specifically for the instillation of wound solutions to the wound bed. They help provide even distribution of wound solutions across the wound bed.

  • The V.A.C. VERAFLO™ Dressing has a higher tensile strength and is less hydrophobic compared to V.A.C. GRANUFOAM™ Dressings.
  • The V.A.C. VERAFLO CLEANSE™ Dressing has the highest tensile strength of all of the dressings. It is customizable for a variety of wound types.
  • Results from a full-thickness porcine wound study indicated that after 7 days of instillation therapy with saline, V.A.C. VERAFLO CLEANSE™ Dressing provided a less robust granulation response than V.A.C. VERAFLO™ Dressing. Although it is uncertain how these results compare to human results, V.A.C. VERAFLO™ Dressing can be considered when the primary goal of therapy is cleansing.
  • Acute, traumatic
  • Dehisced
  • Chronic
  • Pressure ulcers
  • Diabetic foot ulcers
  • Venous ulcers

Any patient who would benefit from vacuum-assisted closure and controlled delivery of topical wound treatment solutions in suspensions over the wound bed could be considered for V.A.C. VERAFLO™ Therapy. This can include patients whose wounds are at risk for infection or suffering from contaminated, colonized, or infected wounds.

V.A.C. VERAFLO™ Therapy provides the wound healing environment of V.A.C.® Therapy with the added benefit of treating the wound bed with automated instillation of topical solutions. Depending on the type of topical solution selected, V.A.C. VERAFLO™ Therapy can aid in the washing, rinsing, hydration, disinfection, and cleansing of the wound bed, while providing all the benefits of negative pressure wound therapy (NPWT).


  • Decreases wound margins
  • Removes exudate
  • Reduces edema
  • Removes infectious material


Promotes granulation tissue formation and perfusions by means of:

  • Cell proliferation
  • Fibroblast migration

3M™ Cavilon™ Skin Prep is a sting-free, alcohol-free liquid barrier film that dries quickly to form a breathable, transparent coating on the skin. It is designed to protect intact or damaged skin from fluids and the effects of friction. It can also be used after dressing application, over the seams or overlaps of the V.A.C.® Advanced Drape to assist in sealing any microleaks that may challenge a secure seal. The barrier film is hypoallergenic and non-cytotoxic. It is provided with all the V.A.C. VERAFLO™ Dressings, except for those sold in the Nordic countries.

The start-up screen takes approximately one minute before the therapy screen is active.

Total time depends on Instill Volume and Soak Time selected. The test cycle completes an abbreviated V.A.C. VERAFLO™ Therapy cycle. Each phase of the cycle will be tested to ensure the system is set up and functioning correctly.
(Please see page 81 of the V.A.C.ULTA™ Therapy System User Manual)

Note: During Test Cycle, Canister Full and V.A.C.® Therapy Blockage Alarms are not functioning, so ensure all clamps are released and canisters are properly engaged prior to initiating the test cycle.

The Leak Alarm Threshold screen is used to set the leak rate threshold that triggers the V.A.C.® Therapy Leak Alarm. Threshold options are Low or High. Low is equal to approximately one liter of air per minute. High is equal to approximately two liters of air per minute. Note: This is not a solution leak alarm.

(Please see page 81 of the V.A.C.ULTA™ Therapy System User Manual)

Note: The High setting is not recommended for use during V.A.C. VERAFLO™ Therapy.

A negative pressure leak occurs when there is a continuous flow above the selected threshold for two minutes.

  • V.A.C.® Therapy Leak Alarm: Occurs when the leak persists for 2 continuous minutes.
  • V.A.C.® Therapy Leak Alarm (Therapy Interrupted): Occurs when a V.A.C.® Therapy Leak Alarm is not resolved within three minutes; the V.A.C.® Therapy Leak Alarm (Therapy Interrupted) will appear and therapy will stop.

(Please see page 81 of the V.A.C.ULTA™ Therapy System User Manual)

The V.A.C. VERAFLO™ Therapy default setting provides a 7-times-daily soak frequency. To see what other clinicians have selected, view the chart below.*


*CAUTION: For illustration purposes only. Reference to a specific solution is not an endorsement of its clinical performance. Consult solution manufacturer instructions for specific use and safety information. V.A.C. VERAFLO™ Therapy is not indicated as a therapy for infected wounds. It can, however, be used as adjunctive treatment in the overall management of infected wounds. V.A.C. VERAFLO™ Therapy is not a replacement for systemic antibiotics. Individual results may vary.

The above topical solutions have been tested and found to be compatible with V.A.C. VERAFLO™ Therapy components. Other compatible topical solutions include benzalkonium chloride, octenidine dihydrochloride (Octenilin®), and mafenide acetate (Sulfamylon®). Contact solution manufacturers for suggested soak/dwell times.

Learn More

For additional information about V.A.C. VERAFLO™ Therapy, visit


  1. Kim PJ, Attinger CE, Steinberg JS, et al. The impact of negative pressure wound therapy with instillation compared with standard negative-pressure wound therapy: a retrospective, historical, cohort, controlled study. Plast Reconstr Surg. 2014;133:709–716.
  2. Brinkert D, Mazen A, Naud M, et al. Negative pressure wound therapy with saline instillation: 131 patient case series. Int Wound J. 2013;10(suppl 1):56-60.
  3. KCI V.A.C.Ulta™ Negative Pressure Wound Therapy System for V.A.C.VeroFlo™ Therapy Collection of Case Studies. 2012. DSL#12-0469.US (Rev 9/12).
  4. Raad W, Lantis JC, Tyrie L, et al. Vacuum-assisted closure instill as a method of sterilizing massive venous stasis wounds prior to split thickness skin graft placement. Int Wound J. 2010;7(2):81-85.
  5. Wolvos T. The use of negative pressure wound therapy with an automated, volumetric fluid administration: an advancement in wound care. Wounds. 2013;25(3):75-83.
  6. Gabriel A, Shores J, Heinrich C, et al. Negative pressure wound therapy with instillation: a pilot study describing a new method for treating infected wounds. Int Wound J. 2008;5(3):399-413.
  7. Wolvos T. Wound instillation—the next step in negative pressure wound therapy. Lessons learned from initial experiences. Ostomy Wound Manage. 2004 Nov;50(11):56-66.

3M and Cavilon are trademarks of 3M Company.

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